Blowpipe apparatus



1943- H. w. JONES BLOWPIPE APPARATUS Filed March 9, 1944 ATTORNEY v INVENTOR HOMER w. JONES BY llll In 1 Patented Dec. 21 1948 BLOWPIPE APPARATUS Homer W. Jones, Westfield, N. J assignor to Union Carbide and Carbon Corporation, a corporation of New York Application March 9, 1944, Serial No. 525,658

8 Claims.

This invention relates to blowpipes and more particularly to post-mixed oxy-fuel gas blowpipes adapted to produce externally mixed flames which are suitable for Welding as well as heating.

A post-mixed blowpipe is disclosed and claimed in the application of Barnes, Burch and Edwards, Serial No. 326,880, filed March 30, 1940, issued August 22, 1944:, as Patent No. 2,356,196. Such post-mixed blowpipe is adapted to produce an externally mixed oxy-fuel gas flame having a stable and well-defined primary combustion zone and a substantially non-luminous secondary combustion zone. In order to obtain such flame, a blowpipe tip is provided having gas outlet passages converging at an acute included angle and adapted to discharge two gas streams at substantially equal velocities, one of the passages being adapted to discharge a stream of fuel gas and the other a stream of oxidizing gas. The axes of the passages lie in the same plane and their discharge orifices coincide in the plane of a surface of the tip to form a common discharge orifice, so that the fuel and oxidizing gas streams collide in the common discharge orifice at the instant the streams discharge from their respective passages, to produce a single combustible oxy-fuel gas stream immediately externally of the tip.

Oxy-fuel gas flames of the post-mixed type produced by such blowpipe as well as oxy-fuel gas flames of the diffusion type, being composed of externally mixed combustible and combustion supporting gases, have the advantage of eliminating flashbacks and backflres, but the shape of the flame is somewhat ragged and of varying character. Furthermore, such flames, prior to the present invention, have not been usable forwelding. They are somewhat inferior to the premixed oxy-iuel gas flames of ordinary blowpipes which are provided with mixers for combining the combustible and combustion-supporting gases within the blowpipe or nozzle to form a combustible gas mixture. Blowpipes and nozzles of the premixed type, however, have the serious drawback of being susceptible to backflres and flashbacks due to an appreciable volume of the combustible gas mixture in the mixed-gas passage between the mixing point and the discharge orifice.

The main object of this invention, therefore, is to provide blowpipe apparatus adapted to produce oxy-fuel gas flames the shape and character of which are equal to the premixed type and which equal the externally mixed type in resistance to flashbacks and backfires; such blowpipe apparatus being simple and economical in its parts, relatively easy and inexpensive to manufacture, and adapted to be readily disassembled for cleaning or replacement. Another object is to provide a method of improving the shape and character of post-mixed oxy-fuel gas flames, making them suitable for welding as well as other purposes.

In general, according to the invention, a postmixed nozzle is provided having an inclined fuelgas passage and an inclined oxidizing gas passage converging to form a common orifice in the bottom of a relatively short mixed-gas passageway in a removable member, such passageway being designed to improve the resulting flame without affecting its resistance to backfire and flashback. The mixed-gas passageway in the removable member is cylindrical, having a length of between inch and 1 inch. A cylindrical passageway approximately A inch long and equal in crosssection to the sum of the cross sections of the gas passages has been found to work well in a blowpipe using about 12 cubic feet of acetylene per hour and a like amount of oxygen. The cross-sectional area of the mixed-gas passageway should be proportional to that of the separate gas discharge passages. As a result, a flame is obtained the shape of which is equal to that of the premixed type, the resistance to flashback and backfire of such flame being equal to that of the externally-mixed type. Furthermore, the nature of such flame may be made oxidizing, neutral, or carburizing, as desired, so that such flame is usable not only for heating and preheating but also for welding ferrous and other metals.

Referring to the drawing:

Fig. 1 is a view mainly in cross-section of a multi-flame blowpipe exemplifying the invention;

Fig. 2 is a View mainly in side elevation of such blowpipe, portions of the blowpipe head being broken away and shown in section;

Fig. 3 is a fragmentary bottom plan view of the multi-flame head shown in Figs. 1 and 2; and

Fig. 4 is a view partly in side elevation and partly in cross-section of a single flame blowpipe nozzle embodying the invention.

The blowpipe B shown in Figs. 1, 2 and 3 of the drawing comprises a head H including a body l0 and a tip I I removably mounted on such body. The tip II is provided with a plurality of uni.-

formly spaced relatively short mixed-gas passageways l2 extending between a raised surface I3 of the body It) and the outer surface or face M of the tip. The passageways 12 are disposed.

in a common plane and in substantially parallel relation with one another. The body I is provided with laterally and downwardly opening corner grooves I5, I5, and the tip H is provided with corresponding upwardly and inwardly facing tongues It, It engaging the grooves i5 so that the tip may be removed readily from the body by sliding the tip with respect to the body in the longitudinal direction of the grooves. The inner surface I? of the tip H fits the raised surface [3 of the body It.

The body it is provided with a pair of spaced substantially parallel gas distributing passages l8 and IQ for a combustible gas and a combustionsupporting gas, respectively. Leading from the gas distributing passage 18 are a series of uniformly spaced gas discharge passages for discharging fuel gas, in this case ace'tylene, at high velocity. A correspondin series of uniformly spaced gas discharge passages 2| lead from the oxidizing gas distributing passage 19 for discharging the combustion-supporting gas, in this case oxygen, at high velocity. Thedischargeorifice of each of the fuel-gas passages 20 coincides with the discharge orifice of an oxidizing gas passage 2| in the plane of the surface 13 of the body H) to form a common discharge orifice 22 at the bottom of each of the mixed-gas passage- Ways F2.

The blowpipe 13 includes an acetylene supply pipe 23 and an oxygen supply pipe 24, the outlet ends of such pipes being silver soldered to the head in in communication with an acetylene passage -25 and'an oxygen passage 26 which, in turn, are in communication with the longitudinal centers of the gas distributing passages l8 and 19,

respectively. The acetylene pipe 23 is connected to a suitable acetylene supply source A by'concluit means including a pressure regulator -27! and a needle valve 28. The oxygen pipe 26 of the blow pipe is likewise connected to a suitable oxygen supply source '0 by conduit means including a pressure regulator -29 and a needle valve 30.

In considering the operation of the blowpipe shown in Figs, 1, 2 and 3, the pressure regulators 2 and 29 are adjusted so as to supply oxygen andacetylene to the blowpi-pe B at substantially equal pressures. are then opened and the gas-discharge passages 20 and -2l discharge oxygentand acetylenestreams which collide in each of the common discharge orifices 22. Theincluded angle between the discharge passages 26 and 21 is acute and such that The needle valves 28 and 30 i the collision between the acetylene and oxygen streams is effective to form a series of combustible gas streams externally of the head H. These combustible gas streams are ignited and burn in free space, each flame having a primary combustion zone the shape of which is somewhat like that of a premixed oxy-acetylene'flame. By adjusting the needle valves 28 and 30, the oxyacetylene flames may be-made neutral or oxidizing or carbonizing, asdesired. r

The length of each of the mixed-gas passageways !2 is preferably of the order of "twice :the diameter -thereof,an'd the cross-sectional area of such passageways, where the inner wall of "the passageways is cylindrical, is preferably proportional to'the cross-sectional areas of the separate gas passages '29 and 2|. Where the shape of the passageways is cylindrical, the cross-sectional area of the passageway preferably is equal at least to the sum of the cross-sectional areas of the passages 20 and 28. The dimensions of the mixed-gas passageways are such that the flames are like post-mixed flames insofar as their re- 4 sistance to flashback and backfire is concerned, and like premixed flames insofar as their shape and nature are concerned, being even suitable for welding.

Referring to Fig. 4 of the drawing, there is shown a single flame blowpipe nozzle N exemplifying the invention, which comprises a body 32 and a tip 33 :rernovably mounted on the body. The tip 33 has a short mixed-gas passageway 34, the internal wall of which is cylindrical, extending between a raised surface 35 of the body and the outer side or face of the tip. The body 32 has separate gas outlet passages 36 and 37 converging at an acute angle, such passages being adapt- :ed to discharge "two gas streams at substantially equal velocities. One of the passages is adapted to discharge a stream of fuel gas and the other a stream of oxidizin gas. The aXes of the passages 3'6 and 3? lie in the same plane and the discharge orifices of the passages coincide in the plane of the surface 35 at the bottom of tlie p'assageway '34 to form a common discharge 38. The convergent gas outlet passages E35 and 3-! are supplied with a suitable combustible :gas and a suitable combustion-supporting gas through separate gas supply passages 39' (and M) in the body Such gas supply passagesare connected 'to sources of the respective gases.

The axes of the convergent passages :36 and 3 are located in a plane which passes through the longitudinal axis of the body 32. Such axis passes through the center of the commonorifice 33, and is in longitudinal alignment with .the longitudinal axis of the mixed-gas passageway 3 The body 3-2 in this modification is provided with a threaded 'outer annular end portion :41 concentric with the longitudinal axis of the body 32, and the tip 3 3 has an annular internally threaded flange d2 engaging the threaded end portion l-rl of the body. This constructional arrangement facilitates the manufacture of the nozzle N, and the assembly may be readily taken apart for cleaning or replacement.

In considering the :operation .of :the :nozzle N shown in Fig. 4, the cross-sectional :area and length of the mixed-gas passageway 34 are adapted to cause the combustible gas mixture stream discharged by the orifice fatty-when ignited, to produce an oxy-fu'el gas flame the shape of which is substantially like that of a premixed oxy-acetylene flame. Such novel structure also produces a flame that equals the externally mixed type in resistance to flashbacksand backfires. Furthermore, the flame :may be used for welding, as .well .as any other purpose for which either a premixed or post-mixed type of flame is suitable.

What is claimed isz 1. In ablowpipe nozzle'the combination with a body of the type adaptedto produce a post-mixed oxy-"fuel-gas fiame, having an inclined fuel-gas passage and an inclined oxidizing-gas passage converging at 'a'comm'on orifice in a surface of the y, wh ch me is subject to undesirable diffused shape rendering it unsuitable for welding, of means for improving the shape of such flame for wel'ding,"said means comprising "a 'tip operatively associated with said body, sald' 'tip hav'ing a mixed-gas passageway extending from said surface to t he'outer surface-of the tip, the cross-sectional area of said passageway being equal at-least to that of both said passages, and theleng'thof said passageway being of theorder *of *twice the diameter of saidpassageway.

{2. In a post-mixed 'oxy-acetylen'e blowpi-pe cataracnozzle-the combination with a body having an oxygen passage and fuel gas passage located in a plane passing through the longitudinal axis of the body, saidpassages converging at an acute included angle toform-atcommon orifice in the plane of a surface of the body at right angles to such axis, which axis passes through the'center of said orifice, said body also having a threaded outer annular end portion concentric with-such axis; of a tip having an annular internally threaded flange engaging the threaded end portion of said body, said tip also having a central mixed-gas passageway the longitudinal axis of which is in alignment with the longitudinal axis of said body, the cross-sectional area of said passageway being equal at least to the sum of the cross-sectional areas of said passages, and length of such passageway being of the order of twice the diameter thereof, such cross-sectional area and length being adapted to cause the combustible gas mixture discharged by such orifice, when ignited, to produce an oxy-fuel gas flame the shape of which is substantially like that of a premixed oxy-fuel gas flame.

3. A blowpipe device comprising a head including a body and a tip mounted on said body, said tip having a plurality of spaced mixed-gas passageways extending between the surface of said body and the outer surface of said tip, said body having separate fuel gas and oxidizing gas distributing passages, and a series of spaced outlet passages leading from such oxidizing gas distributing passage for discharging oxidizing gas streams at high velocity, and a series of spaced outlet passages leading from such fuel gas distributing passage for simultaneously discharging fuel streams at high velocity, the discharge orifice of each of said fuel gas passages coinciding with the discharge orifice of an oxidizing gas passage in the plane of said surface of said body to form a common discharge orifice at the bottom of each of said mixed-gas passageways, the fuel and oxidizing gas passages of each orifice being equally inclined with respect to said plane, whereby said outlet passages are adapted to discharge oxygen and fuel-gas streams which collide in such common discharge orifices, the included angle between said coinciding outlet passages being such that the collision between said oxidizing and fuel-gas streams is effective to form a series of combustible gas streams externally of said head, said combustible gas streams, when ignited, being adapted to produce high temperature flames each having a primary combustion zone, and means for supplying such oxidizing and fuel-gas streams, respectively, in such proportions that a combustible mixture is produced in each of said primary combustion zones, the cross-sectional area of each passageway being equal at least to the sum of the crosssectional areas of each pair of passages, and the length of each passageway being of the order of twice the diameter thereof,- the length and crosssectional area of said passageways being such that flashbacks and backfires of such flames are inhibited while the shape of such flames is like that of a premixed flame.

4. An externally mixed flame blowpipe device as defined by claim 3, in which said oxidizing-gas passages are arranged in parallel relation to one another in a common plane, and said fuel-gas discharge passages are arranged in parallel relation with one another in a common plane.

5. An externally mixed flame blowpipe device as defined by claim 3, in which the mixed-gas passageways "said tip are arranged in spaced parallel ;relation with one another in a common plane,'and the common orifice atthe bottom of each mixed-gas passageway is located centrally with respect to such passageway; 1

6. An externally mixed flame blowpipe device as defined; by claim 3, in which said body is provided with laterally and downwardly opening grooves, and said tip is provided with upwardly andinwardly facing tongues fitting said grooves so that the tip may be removed from the body by sliding the tip with respect to the body in the direction of said grooves.

7. A blowpipe nozzle comprising, in comblnation, a body having a pair of gas passages converging to a common orifice in a surface of said body, each of said passages being inclined the same degree to the axis of said orifice and said passages being adapted to discharge two gas streams at substantially equal velocities, one of said passages being adapted to discharge a stream of fuel gas and the other of said passages being adapted to discharge a stream of oxidizing gas, so that these two streams will collide at said orifice to produce a single combustible gas stream, and a tip removably secured to said body and having a combustible gas passageway extending therethrough and coaxial with said orifice, the inner surface of said tip engaging the surface of said body around said orifice and the inner end of said passageway communicating directly with said orifice, so that said single gas stream will flow through said passageway and, when ignited as it discharges from said passageway, will produce a high temperature flame having a premixed type of primary combustion zone, the cross-sectional area of said passageway being equal at least to the sum of the cross-sectional areas of said passages, and the length of said passageway being of the order of twice the diameter of such passageway, whereby flashbacks and backfires of such flame are inhibited while the shape of such flame is like that of a premixed flame.

8. A blowpipe nozzle having a mixed-gas passageway extending to the outer face of the nozzle, gas passages converging at an acute angle to form a common orifice communicating directly with the inner end of said passageway, the axes of said gas passages forming equal angles with the axis of the passageway, said passages being adapted to discharge two gas streams at substantially equal velocities, one of said passages being adapted to discharge a stream of fuel gas and the other of said passages being adapted to discharge a stream of oxidizing gas, whereby such fuel-gas stream and such oxidizing gas stream will collide at the instant that both of said streams discharge from their respective passages, to produce a single combustible gas stream which flows through said passageway, said single gas stream, when ignited as it discharges from said passageway, being adapted to produce a high temperature flame having a premixed type of primary combustion zone, the length and cross-sectional area of said passageway being such that flashbacks and backfires of such flame are inhibited while the shape of such flame is like that of a premixed flame, the cross-sectional area of said passageway bein at least equal to the sum of the cross-sectional areas of said passages, and the length of said passageway being of the order of twice the diameter of said passageway.

HOMER W. JONES.

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